In Ubuntu 18.04 , the Show Application icon is at the bottom of the Dock.If you have Windows experience you may feel better if it locates on the top but not bottom to make Ubuntu much like Windows
To move the Show Application icon to top , the simplest way is to use gsettings command . Maybe you hate command line ,but that what Ubuntu is , you need to install another tool or application without using command line.
Right-click your Ubuntu desktop then click Open Terminal (Or by pressing Ctl+Alt+t) , then input below command and press Enter , it’s done ,so simple.
gsettings set org.gnome.shell.extensions.dash-to-dock show-apps-at-top true
If you want to revert it back ,just issue below command
gsettings set org.gnome.shell.extensions.dash-to-dock show-apps-at-top false